Method of finishing a knitted paper fabric



Dec. 27, 1966 B. KIMBALL 3,293,724

METHOD OF FINISHING A KNITTED PAPER FABRIC Filed April 1'7, 1964 AM o 1G v mm MOM INVENTOR BENJAMIN KIMBALL BYW ATTORNEY United States Patent3,293,724 METHOD OF FINISHING A KNITTED PAPER FABRIC Benjamin Kimball,Gilman, Vt., assignor to Gilman Paper Company, New York, N .Y., acorporation of New Hampshire Filed Apr. 17, 1964, Ser. No. 360,656 1Claim. (Cl. 2876) This invention relates generally to textiles, and isespecially concerned with a unique textile construction and method ofmanufacture.

While the textile and method of manufacture of the present inventionhave been primarily developed and employed for use in bags forcontaining granular material, such as sandbags and the like, and will beillustrated and described hereinafter with particular reference thereto,it is appreciated that the advantageous features of the invention arecapable of many varied applications, all of which are intended to becomprehended herein.

It is an important object of the present invention to provide a fabricand method of fabric manufacture for use in sandbags and the like, whicheffectively reduces sifting and greatly increases strength.

It is a further object of the present invention to provide a bagconstruction and method of the type described, which is extremelyeconomical in manufacture, durable and reliable in use, and wherein thefabric surface may be printed as desired, to provide a neat andattractive appearance.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawings,which form a material part of this disclosure.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts which will beexemplified in the construction hereinafter described, and of which thescope will be indicated by the appended claim.

In the drawings:

FIGURE 1 is a diagrammatic representation of the method of the presentinvention.

FIGURE 2 is a perspective view illustrating a bag constructed inaccordance with the teachings of the present invention.

FIGURE 3 is a fragmentary view, greatly enlarged, showing an area ofknit fabric of the prior art.

FIGURE 4 is a sectional view taken generally along the line 44 of FIG.3.

FIGURE 5 is a fragmentary area, greatly enlarged, showing knit fabric ofthe instant invention.

FIGURE 6 is a sectional view taken generally along the line 66 of FIGURE5.

Referring now more particularly to the drawings, and specifically toFIGURE 2 thereof, a bag is there generally designated 10 and may beformed of knit fabric 11. The fabric 11 may be tubular, as produced byconventional tubular knitting machines and is knit of cellulose yarn,preferably paper yarn having a twist of from one to ten turns per inch.Prior to knitting, the cellulose or paper yarn may advantageously betreated with a wet-strength resin of suitable composition, and ifdesired, also with a fungus preventative.

The tubular knit fabric 11 may have one end closed, as by stitching 12,the other end being illustrated as open and provided with a tie string13 for securement or closure after filling.

In FIGURE 5 is shown an enlarged fragmentary area of the fabric 11,wherein it will be observed that the needle holes or interstitialopenings are relatively small, the individual yarns having been spreador widened and squeezed toward each other to produce this desiredresult, as will appear more fully hereinafter.

It is also shown in FIGURE 6 that the fabric 11 is relatively thin anddense, the surfaces thereof being relatively smooth.

The above characteristics of the fabric 11 are best noted by comparisonto the prior-art fabric 11a of FIG URES 3 and 4. It is there seen thatthe interstitial spaces or needle holes are relatively large, theindividual yarns being relatively thin, and the fabric surfaces beingrelatively rough.

The method of the instant invention may be considered as employing theprior-art fabric 11a as a starting material, with the resultant productof the instant invention being fabric 11 having the increasedinterlocking action of yarns and above-mentioned additional advantageouscharacteristics.

In the diagrammatic representation of FIGURE 1, a supply roll isdesignated 20 and may supply a web of fabric 11a, such as that of theprior art illustrated in FIGURES 3 and 4. Thus, the fabric 11a isconventionally knit of cellulose or paper yarn and may be of single ordouble thickness, the latter as produced by tubular knitting. Of course,the supply roll 20 may be replaced by a tubular knitting machine fordirect feeding therefrom of the knit fabric 11a.

From the supply roll 20, the knit fabric 11a may be subjected tosoftening, as by the application of steam at 21. The softening station21 may apply steam from both sides of the web for more thoroughsoftening of the yarns, if desired.

After softening, the fabric 11a passes between the nip of pressure orcalendering rolls 22, The calendering rolls 22 may -be of any suitablecharacter, such as of steel, granite, hard rubber or the like, and serveto squeeze therebetween the fabric under a pressure of approximately 25tons. This calendering action produces the above-described novel andadvantageous characteristics of the resultant product, effectivelysmoothing the surfaces of the fabric to the extent that it can beprinted, increasing the interlock of yarns, substantially closing theneedle holes, and effectively reducing the caliper or thickness of thefabric, say on the order of 50%, decreasing the stretch of the fabric,resulting in the bag retaining its original shape.

The fabric passing from the calendering rolls 22 is designated 11b andpasses thence to a drying station or drier 23, which may consist ofheated rolls or other suitable drying means to insure removal ofmoisture and effectively set the fabric in its calendered condition.

The finished fabric 11 exits from the drier station 23 where it isconveyed by a conveyor 24 to a cutter or knife 25 for severance intolengths suitable for bag formation.

In practice, a resultant bag 10 of the present invention is competitivewith a jute bag and reduces sifting by approximately 50% over that ofthe jute bag. Further, the calendering of the knit cellulose fabricgreatly reduces stretch of the fabric to considerably enhance bagstrength to far beyond that of the jute bag.

From the foregoing, it is seen that the present invention provides ahighly advantageous textile product and method of manufacture whichfully accomplish their intended objects and are well adapted to meetpractical conditions of manufacture and use.

Although the present invention has been described in some detail by wayof illustration and example for purposes of clarity of understanding, itis understood that certain changes and modifications may be made withinthe spirit of the invention and scope of the appended claim.

Patented Dec. 27, 1966 What is claimed is:-

In the art of textile manufacturing, the method of making knitted paperbags which comprises:

(a) knitting twisted wet-strength paper yarn into a tubular fabric on atubular knitting machine, (b) removing said knitted tube from saidmachine and flattening said tube, (c) applying steam to both sides ofthe flattened tube, (d) passing the steamed flattened tube betweencalendering rolls under a pressure of approximately 25 tons, thusincreasing the interlock of yarns, substantially closing the needleholes to reduce the sand sift loss, effectively decreasing the stretchof the fabric, and substantially increasing the strength thereof, (e)drying the flattened tube to insure the removal of moisture andeffectively set the fabric in its calendered condition, and

(f) then cutting the flattened tube into suitable lengths for sandbagformation.

References Cited by the Examiner UNITED 15 MERVIN STEIN, PrimaryExaminer.

R. FELDBAUM, Assistant Examiner.

